The invention relates to a lockable coupling device in particular for folding devices.
In folding devices with three or a greater number of folding elements arranged within a frame, one folding element that is opened first when opening the folding device is arranged pivotably on the neighboring folding element. When the first folding element is opened, for example, by approximately 90° and subsequently the neighboring second folding element is also opened, an increased load caused by the weight and leverage of the first folding element is acting on the second folding element. This can cause undesirable deformations of the second folding element which may lead to false positioning of both folding elements and also of further folding elements relative to the frame and, for example, can cause functional restrictions or loss of comfort in operating the folding device, for example, due to contacting and dragging of the bottom side of the folding elements on the floor when opening the folding elements.
It is therefore preferred that, prior to opening the second folding element, the first folding element is placed against the second folding element (opening angle of the first element of approximately 180°) and is secured in this position. This connection should be existing until the second folding element has reached the closed position again.
A coupling device that ensures this is disclosed in EP 0 342 420 B2. In this reference, a three-panel folding wall together with locking system with strictly prescribed locking sequence is described. Here, a first folding element can be pivoted against a second folding element by approximately 180° and can be fixed in this position. A mechanism prevents that the first folding element detaches from the second folding element when the second folding element is not in the closed position. Moreover, a second mechanism effects that the second folding element can be opened only once the first folding element has been secured at the second folding element. Observing this locking sequence is ensured by two different devices, and each device comprises a great number of components. This is disadvantageous in regard to production, assembly, and servicing of the device.
In practice, a lockable coupling devices is also known which comprises a latch whose two parts are attached to the folding elements that are to be fixed in position. In the female part of the latch, a hook that is loaded by a spring force and is rotatably supported is installed which locks the connection of the latch parts when they latch relative to each other. The hook comprises an angled lever extension which is projecting out of the female part of the latch. This projecting part acts as a sensing device that projects rearwardly past a horizontal or vertical boundary part of the second folding element. In a closed position of the second folding element, either a neighboring third folding element or the frame is pushing against the sensing device and unlocks the latching connection. A disadvantage of this device is that the sensing device can also be triggered by hand. Also, an exchange of individual parts is relatively complicated so that in case of defects usually the entire device must be exchanged.
The invention has the object to avoid the aforementioned disadvantages of the prior art and to provide a coupling device for a folding device with at least three folding elements that is as simple as possible and lockable, wherein the coupling device locks a releasably lockable coupling between a first folding element and a second folding element when the second folding element is not in the closed position and unlocks it when the second folding element is in the closed position.